Native vs. Custom Merge: Two Ways to Combine Records in HubSpot and Salesforce

Native merge and Synthetic merge are two independent methods for combining duplicate records. Both methods support Insycle's master selection rules and field data retention rules — choosing one over the other does not prevent you from using the full range of configuration options available in Step 3.

• Native merge uses your CRM's built-in merge logic. In HubSpot, this uses HubSpot's native merge behavior. In Salesforce, this uses Salesforce's Apex API merge logic. Native merge follows your CRM's standard rules for consolidating fields, associations, and activities during a merge.
• Synthetic merge uses Insycle's custom merge logic. Synthetic merge gives you more control over field retention and master selection than your CRM's native merge provides. It is also the only option available for object types that do not have native merge support in your CRM.

Note: Choosing Native merge does not lock you into your CRM's default field behavior. You can use Native merge for its speed and compatibility benefits while still applying Insycle's custom field retention rules on top.

The image above shows the Method tab in Step 3 of the Merge Duplicates module, with the Merge API set to Synthetic and the Blank Fields toggled right/enabled, set to Fill.

How Native and Synthetic Merge Differ

Native and Synthetic merge differ in two ways that apply across both HubSpot and Salesforce.

Record ID behavior:

• With Native merge, a new unique Record ID is created for the resulting merged record.
• With Synthetic merge, the Record ID from the master record is kept. No new record is created.

Processing time:

• Native merge is generally faster.
• Synthetic merge is more complex and takes longer to run, particularly when records have a large number of associated objects, engagements, or relationships to reassign. When running a Synthetic merge in Update mode, Insycle displays a confirmation prompt with an estimated processing time before the operation begins. Avoid running multiple Synthetic merge operations in parallel on the same database.

HubSpot-Specific Differences

• Email address consolidation — When merging contacts using Native merge, the master record's email address becomes the primary, and email addresses from duplicate records are added as additional addresses.
• Associated leads on companies — When merging companies using Native merge, the associated leads from duplicate companies are transferred to the master company after the merge. When merging companies using Synthetic merge, Insycle automatically recreates leads from duplicate companies and associates them with the master company, preserving the original lead name, type, stage, and owner. This is necessary because HubSpot's API prevents existing lead objects from being reassigned to a different company.
• 250-merge limit — HubSpot limits Native merges to 250 records per master record. Synthetic merge bypasses this restriction.

Salesforce-Specific Differences

• Relationship relinking — For Opportunities and custom objects, Synthetic merge uses Salesforce's CRUD API to inspect schema metadata and automatically re-parent all related objects from duplicate records into the master record.
• Contacts, leads, and accounts — Synthetic merge for these object types is available on request but is slower and offers limited control over deeply nested relationships. Native merge is the recommended method for contacts, leads, and accounts in Salesforce.

Insycle sets a default merge method based on your CRM and object type. You can change this default on the Method tab in Step 3.

Synthetic merge is the right choice in the following situations:

• You need to keep the master record's ID — Synthetic merge preserves the master record's existing ID rather than creating a new one — this applies to both HubSpot and Salesforce, and is important when other systems reference that ID. 

For HubSpot only:

• You are merging companies with Salesforce sync enabled — Native merge is not available for HubSpot companies when the HubSpot-Salesforce sync is active. Synthetic is the default and required method in this case.
• You have more than 250 duplicates merging into a single record — HubSpot limits Native merges to 250 records per master. Synthetic merge bypasses this restriction.
• You need records merged into a parent-child company hierarchy — Synthetic merge handles complex parent-child association reassignments that Native merge may not resolve correctly.
• You may need to partially revert a merge later — Synthetic merge supports partial restoration of merged records. Native merge does not.

For Salesforce only:

• You are merging Opportunities or custom objects — Synthetic is the default and only available method for these object types in Salesforce.

Note: The Method tab is available only for HubSpot and Salesforce. If you do not see this tab in Step 3, your CRM does not support this setting.

1. Navigate to Data Management > Merge Duplicates and select your database and object type.
2. In Step 1, configure your matching fields to identify potential duplicates, then click Find.
3. In Step 2, review the duplicate groups to confirm the results look correct before proceeding.
4. In Step 3, click the Method tab.
5. Under Merge API, select Native or Synthetic.

The image above shows the Method tab in Step 3 of the Merge Duplicates module, with the Merge API set to Native and the Blank Fields toggled right/enabled, set to Fill.

The way Native and Synthetic merge handle specific field types, associations, and activities differs between HubSpot and Salesforce. For details on how each method behaves in your CRM:

• For HubSpot-specific Native and Synthetic merge behavior, see HubSpot Merge Duplicates Overview.
• For Salesforce-specific Native and Synthetic merge behavior, see Salesforce Merge Duplicates Overview.